#quant
6 posts3 participants0 posts today
"Controlling quantum entanglement with classical non-separable light"
https://arxiv.org/abs/2507.06462 #Physics.Optics #Dynamics #Quant-Ph #Matrix
arXiv.orgControlling quantum entanglement with classical non-separable lightHere we investigate the quantum frequency conversion of entangled photons driven by a classically non-separable laser beam. We show that the frequency conversion dynamics is described by a quantum channel that stems from the classical drive field through the channel-state duality - the quantum channel is dual to the classical coherence matrix of the drive field. This implies that the evolution of entanglement in the conversion process is bound by the classical non-separability of the drive field, a result that we confirm experimentally. Furthermore, we show that the conversion dynamics can be understood as a swapping operation between classical non-separability and entanglement, unveiling a physical connection between two fundamentally different concepts.
"Geometric Invariants of Quantum Metrology"
https://arxiv.org/abs/2507.06128 #Physics.Atom-Ph #Quant-Ph #Dynamics #Matrix
arXiv.orgGeometric Invariants of Quantum MetrologyWe establish a previously unexplored conservation law for the Quantum Fisher Information Matrix (QFIM) expressed as follows; when the QFIM is constructed from a set of observables closed under commutation, i.e., a Lie algebra, the spectrum of the QFIM is invariant under unitary dynamics generated by these same operators. Each Lie algebra therefore endows any quantum state with a fixed "budget" of metrological sensitivity -- an intrinsic resource that we show, like optical squeezing in interferometry, cannot be amplified by symmetry-preserving operations. The Uhlmann curvature tensor (UCT) naturally inherits the same symmetry group, and so quantum incompatibility is similarly fixed. As a result, a metrological analog to Liouville's theorem appears; statistical distances, volumes, and curvatures are invariant under the evolution generated by the Lie algebra. We discuss this as it relates to the quantum analogs of classical optimality criteria. This enables one to efficiently classify useful classes of quantum states at the level of Lie algebras through geometric invariants.
"The robustness of composite pulses elucidated by classical mechanics: Stability around the globe"
https://arxiv.org/abs/2507.01364 #Physics.Class-Ph #Physics.Atom-Ph #Mechanical #Mechanics #Quant-Ph #Matrix
arXiv.orgThe robustness of composite pulses elucidated by classical mechanics: Stability around the globeComposite Pulses (CPs) are widely used in Nuclear Magnetic Resonance (NMR), optical spectroscopy, optimal control experiments and quantum computing to manipulate systems that are well-described by a two-level Hamiltonian. A careful design of these pulses can allow the refocusing of an ensemble at a desired state, even if the ensemble experiences imperfections in the magnitude of the external field or resonance offsets. Since the introduction of CPs, several theoretical justifications for their robustness have been suggested. In this work, we suggest another justification based on the classical mechanical concept of a stability matrix. The motion on the Bloch Sphere is mapped to a canonical system of coordinates and the focusing of an ensemble corresponds to caustics, or the vanishing of an appropriate stability matrix element in the canonical coordinates. Our approach highlights the directionality of the refocusing of the ensemble on the Bloch Sphere, revealing how different ensembles refocus along different directions. The approach also clarifies when CPs can induce a change in the width of the ensemble as opposed to simply a rotation of the axes. As a case study, we investigate the $90(x)180(y)90(x)$ CP introduced by Levitt, where the approach provides a new perspective into why this CP is effective.
Quant ist weg!
Nicht weg, sondern in all meinen (Scheiß-) Firefox -V140.0-Installationen auf Android lässt sich seit ca. vorgestern die Suchmaschine Quant nicht mehr nutzen - und alle Fireföxe haben sie sogar als gesetzte Standardsuchmaschine rausgeworfen und durch Google ersetzt.
Gleich vorweg: Es liegt nicht am eingestellten Suchstring bzw. Aufrufformat.
Im Fi
"Natural Intelligence: the information processing power of life"
https://arxiv.org/abs/2506.16478 #Dynamics #Q-Bio.Ot #Quant-Ph #Cell
arXiv.orgNatural Intelligence: the information processing power of lifeMerely by existing, all physical systems contain information, and physical dynamics transforms and processes that information. This note investigates the information processing power of living systems. Living systems harvest free energy from the sun, from geothermal sources, and from each other. They then use that free energy to drive the complex set of chemical interactions that underlie life. All molecules -- be they simple molecules such as water, or complex molecules such as DNA -- register information via their chemical composition. When these molecules undergo chemical reactions, that information is transformed and processed. These chemical transformations can be thought of as elementary logical operations: such bio-ops include the absorption of a photon in a chromophore during photosynthesis, the formation or breaking of covalent, hydrogen, and van der Waals bonds in the process of metabolism and reproduction, or the release of a neurotransmitter molecule when a synapse fires in the brain. This paper estimates the total number of bio-ops that have been, and are being performed, by life on earth. We find that the current number of bio-ops performed by all life on earth is around $10^{33}-10^{35}$ bio-ops per second. The cells in an individual human being perform around $10^{20}-10^{22}$ bio-ops per second, comparable to the information processing power of all the computers, cell phones, and server farms on earth. Depending on how one defines a neural operation, at most a few percent of human bio-ops take place in the firing of neurons and synapses in the brain. Over the course of life on earth, about $10^{50}-10^{52}$ bio-ops have taken place.
Neue, datenschutfreundliche Suchmaschine: Murena Find
#Suchmaschine #quant #Datenschutz #privacy #MurenaFind
https://www.linux-magazin.de/news/neue-datenschutfreundliche-suchmaschine-murena-find/
Linux-Magazin · Neue, datenschutfreundliche Suchmaschine: Murena FindMurena, ein Hersteller nachhaltiger und quelloffener Smartphones, die insbesondere auch die Privatsphäre schützen, hat nun in Zusammenarbeit mit Quant, einer datenschutzfreundlichen Suchmaschine den Service Murena Find gelauncht. Murena Find wirbt für sich mit dem Versprechen, keine persönlichen Daten zu vermarkten, keine Werbeprofile zu erstellen, keine Suchdaten zu speichern und vollständig in Europa gehostet zu sein. Es ist damit ein weiterer Schritt zur völligen Unanhängigkeit von Google. Murena Find ist ab sofort die Standard-Suchmaschine auf Murena-Smartphones unter /e/OS 3.0 und soll bald auch über die Cloud-Plattform Murena-Workspace verfügbar sein.
Had ik jullie al verteld dat Quant best regelmatig met weinig resultaten al gelijk uitstekende resultaten voorschotelt?
Qwant - De [Franse] zoekmachine met respect voor uw privacy
https://www.qwant.com/
QwantQwantFast, reliable answers and still in trust: Qwant does not store your search data, does not sell your personal data and is hosted in Europe.
Murena + Quant = Murena Find
https://linuxnews.de/murena-quandt-murena-find/ #murena #quant
LinuxNews.de · Murena + Quandt = Murena Find
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@inlovewithpda I am using #quant for quite some time, and I am happy with it …
"Dynamic and Geometric Shifts in Wave Scattering"
https://arxiv.org/abs/2506.07144 #Physics.Optics #Mechanics #Quant-Ph #Matrix
arXiv.orgDynamic and Geometric Shifts in Wave ScatteringSince Berry's pioneering 1984 work, the separation of geometric and dynamic contributions in the phase of an evolving wave has become fundamental in wave physics, underpinning diverse phenomena in quantum mechanics, optics, and condensed matter. Here we extend this geometric-dynamic decomposition from the wave-evolution phase to a distinct class of wave scattering problems, where observables (such as frequency, momentum, or position) experience shifts in their expectation values between the input and output wave sates. We describe this class of problems using a unitary scattering matrix and the associated generalized Wigner-Smith operator (GWSO), which involves gradients of the scattering matrix with respect to conjugate variables (time, position, or momentum, respectively). We show that both the GWSO and the resulting expectation-values shifts admit gauge-invariant decompositions into dynamic and geometric parts, related respectively to gradients of the eigenvalues and eigenvectors of the scattering matrix. We illustrate this general theory through a series of examples, including frequency shifts in polarized-light transmission through a time-varying waveplate (linked to the Pancharatnam-Berry phase), momentum shifts at spatially varying metasurfaces, optical forces, beam shifts upon reflection at a dielectric interface, and Wigner time delays in 1D scattering. This unifying framework illuminates the interplay between geometry and dynamics in wave scattering and can be readily applied to a broad range of physical systems.
"Quantum Cognition Machine Learning for Forecasting Chromosomal Instability"
https://arxiv.org/abs/2506.03199 #Mechanical #Quant-Ph #Q-Bio.Qm #Cs.Lg #Cell
arXiv.orgQuantum Cognition Machine Learning for Forecasting Chromosomal InstabilityThe accurate prediction of chromosomal instability from the morphology of circulating tumor cells (CTCs) enables real-time detection of CTCs with high metastatic potential in the context of liquid biopsy diagnostics. However, it presents a significant challenge due to the high dimensionality and complexity of single-cell digital pathology data. Here, we introduce the application of Quantum Cognition Machine Learning (QCML), a quantum-inspired computational framework, to estimate morphology-predicted chromosomal instability in CTCs from patients with metastatic breast cancer. QCML leverages quantum mechanical principles to represent data as state vectors in a Hilbert space, enabling context-aware feature modeling, dimensionality reduction, and enhanced generalization without requiring curated feature selection. QCML outperforms conventional machine learning methods when tested on out of sample verification CTCs, achieving higher accuracy in identifying predicted large-scale state transitions (pLST) status from CTC-derived morphology features. These preliminary findings support the application of QCML as a novel machine learning tool with superior performance in high-dimensional, low-sample-size biomedical contexts. QCML enables the simulation of cognition-like learning for the identification of biologically meaningful prediction of chromosomal instability from CTC morphology, offering a novel tool for CTC classification in liquid biopsy.
"On the Potential of Microtubules for Scalable Quantum Computation"
https://arxiv.org/abs/2505.20364
#Physics.Bio-Ph #Microtubule #Quant-Ph
arXiv.orgOn the Potential of Microtubules for Scalable Quantum ComputationWe examine the quantum coherence properties of tubulin heterodimers in the Microtubule (MT) lattice. In the cavity-MT model proposed by the authors, according to which the MT interiors are modeled as high-Q quantum-electrodynamics cavities, decoherence-resistant entangled states have been argued to emerge under physiological conditions, with decoherence times of order $\mathcal{O}(10^{-6})$ s. The latter is the result of strong electric-dipole interactions of tubulin dimers with ordered-water dipole quanta in the MT interior. We re-interpret the classical nonlinear (pseudospin) $σ$-models, describing the emergent dynamics of solitonic excitations in such systems, as representing quantum coherent (or possibly pointer) states, arising from the incomplete collapse of quantum-coherent dipole states. These solitons mediate dissipation-free energy transfer across the MT networks. We underpin logic-gate-like behavior through MT-associated proteins and detail how these structures may support scalable, ambient-temperature quantum computation, with the fundamental unit of information storage being a quDit associated with the basic unit of the MT honeycomb lattice. We describe in detail the decision-making process, after the action of an external stimulus, during which optimal path selection for energy-loss-free signal and information transport across the MT network emerges. Finally, we propose experimental pathways, including Rabi-splitting spectroscopy and entangled surface plasmon probes, to experimentally validate our predictions for MT-based, scalable quantum computation.
"On the Potential of Microtubules for Scalable Quantum Computation"
https://arxiv.org/abs/2505.20364 #Physics.Bio-Ph #Microtubule #Quant-Ph #Dynamics
arXiv.orgOn the Potential of Microtubules for Scalable Quantum ComputationWe examine the quantum coherence properties of tubulin heterodimers in the Microtubule (MT) lattice. In the cavity-MT model proposed by the authors, according to which the MT interiors are modeled as high-Q quantum-electrodynamics cavities, decoherence-resistant entangled states have been argued to emerge under physiological conditions, with decoherence times of order $\mathcal{O}(10^{-6})$ s. The latter is the result of strong electric-dipole interactions of tubulin dimers with ordered-water dipole quanta in the MT interior. We re-interpret the classical nonlinear (pseudospin) $σ$-models, describing the emergent dynamics of solitonic excitations in such systems, as representing quantum coherent (or possibly pointer) states, arising from the incomplete collapse of quantum-coherent dipole states. These solitons mediate dissipation-free energy transfer across the MT networks. We underpin logic-gate-like behavior through MT-associated proteins and detail how these structures may support scalable, ambient-temperature quantum computation, with the fundamental unit of information storage being a quDit associated with the basic unit of the MT honeycomb lattice. We describe in detail the decision-making process, after the action of an external stimulus, during which optimal path selection for energy-loss-free signal and information transport across the MT network emerges. Finally, we propose experimental pathways, including Rabi-splitting spectroscopy and entangled surface plasmon probes, to experimentally validate our predictions for MT-based, scalable quantum computation.
"Reduced Density Matrices and Phase-Space Distributions in Thermofield Dynamics"
https://arxiv.org/abs/2505.21302 #Physics.Chem-Ph #Quant-Ph #Dynamics #Matrix
arXiv.orgReduced Density Matrices and Phase-Space Distributions in Thermofield DynamicsThermofield dynamics (TFD) is a powerful framework to account for thermal effects in a wavefunction setting, and has been extensively used in physics and quantum optics. TFD relies on a duplicated state space and creates a correlated two-mode thermal state via a Bogoliubov transformation acting on the vacuum state. However, a very useful variant of TFD uses the vacuum state as initial condition and transfers the Bogoliubov transformation into the propagator. This variant, referred to here as the inverse Bogoliubov transformation (iBT) variant, has recently been applied to vibronic coupling problems and coupled-oscillator Hamiltonians in a chemistry context, where the method is combined with efficient tensor network methods for high-dimensional quantum propagation. In the iBT/TFD representation, the mode expectation values are clearly defined and easy to calculate, but the thermalized reduced particle distributions such as the reduced 1-particle densities or Wigner distributions are highly non-trivial due to the Bogoliubov back-transformation of the original thermal TFD wavefunction. Here we derive formal expressions for the reduced 1-particle density matrix (1-RDM) that uses the correlations between the real and tilde modes encoded in the associated reduced 2-particle density matrix (2-RDM). We apply this formalism to define the 1-RDM and the Wigner distributions in the special case of a thermal harmonic oscillator. Moreover, we discuss several approximate schemes that can be extended to higher-dimensional distributions. These methods are demonstrated for the thermal reduced 1-particle density of an anharmonic oscillator.